What did you use as an antenna with the BCT8, and how good was the reception? If you use that same antenna, you should get similar results and if you don't, then it may indicate a problem with the BCT15. But I would be more inclined to think that the new scanner is working fine and that the long wire that you can stick on the glass isn't really doing the job and pulling in signals.
My experience with scanners in the vehicle is this: using a rubber duck or piece of wire inside the vehicle just doesn't do it because of the metal and glass reflecting the radio signals instead of capturing them. If you want the best reception possible, I suggest putting an antenna on the outside of the vehicle and they come in all types and mountings...magnet mount, drill a hole and mount it, or a trunk mount base (which I prefer). Any of these will give you much better reception over what you're using right now.
The place that sold you the new scanner should be able to point out some antennas that will give you better results. Hope this helps..
Russell
